Posterior Crico-Arytenoid (Left) (Musculus cricoarytenoideus posterior)
Educational content only — not medical advice.
Anatomy
The posterior crico-arytenoid is a paired intrinsic laryngeal muscle situated on the posterior surface of the cricoid lamina. It is the sole abductor of the vocal folds, rotating the muscular processes of the arytenoid cartilages medially to swing the vocal processes laterally. It is vital for life as it maintains patency of the rima glottidis during respiration.
Origin & insertion
From the shallow depression on the posterior surface of the cricoid cartilage lamina to the muscular process of the arytenoid cartilage.
Action
Abducts the vocal folds, opening the rima glottidis to allow air entry during inspiration.
Innervation
Recurrent laryngeal nerve (branch of vagus nerve, cranial nerve X).
Clinical notes
Bilateral recurrent laryngeal nerve injury results in paralysis of both posterior crico-arytenoids, causing the vocal folds to remain adducted in the midline with life-threatening airway obstruction requiring emergency tracheostomy (Semon law).
Related structures
Educational references
FAQ
What is the role of the Posterior Crico-Arytenoid (Left)?
The posterior crico-arytenoid is a paired intrinsic laryngeal muscle situated on the posterior surface of the cricoid lamina. It is the sole abductor of the vocal folds, rotating the muscular processes of the arytenoid cartilages medially to swing the vocal processes laterally. It is vital for life as it maintains patency of the rima glottidis during respiration.
Why is the Posterior Crico-Arytenoid (Left) clinically important?
Bilateral recurrent laryngeal nerve injury results in paralysis of both posterior crico-arytenoids, causing the vocal folds to remain adducted in the midline with life-threatening airway obstruction requiring emergency tracheostomy (Semon law).
Source & license
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